All i.MX SoCs except i.MX1 have ONLY one necessary IRQ, use
platform_get_irq_optional() to get second/third IRQ which are
optional to avoid below error message during probe:

[    0.726219] imx-uart 30860000.serial: IRQ index 1 not found
[    0.731329] imx-uart 30860000.serial: IRQ index 2 not found

Fixes: 7723f4c5 ("driver core: platform: Add an error message to platform_get_irq*()")
Signed-off-by: NAnson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1570614559-11900-1-git-send-email-Anson.Huang@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix Sphinx warning in serial_core.c:

../drivers/tty/serial/serial_core.c:1969: WARNING: Definition list ends without a blank line; unexpected unindent.

Fixes: 73abaf87 ("serial: earlycon: Refactor parse_options into serial core")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/e989641c-224a-1090-e596-e7cc800bed44@infradead.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There are two checks to see if the manual gpio is configured, but
these the check is seeing if the structure is NULL instead it
should check to see if there are CTS and/or RTS pins defined.

This patch uses checks for those individual pins instead of
checking for the structure itself to restore auto RTS/CTS.
Signed-off-by: NAdam Ford <aford173@gmail.com>
Reviewed-by: NYegor Yefremov <yegorslists@googlemail.com>
Link: https://lore.kernel.org/r/20191006163314.23191-2-aford173@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When using mctrl_gpio_to_gpiod, it dereferences gpios into a single
requested GPIO.  This dereferencing can break if gpios is NULL,
so this patch adds a NULL check before dereferencing it.  If
gpios is NULL, this function will also return NULL.
Signed-off-by: NAdam Ford <aford173@gmail.com>
Reviewed-by: NYegor Yefremov <yegorslists@googlemail.com>
Link: https://lore.kernel.org/r/20191006163314.23191-1-aford173@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix incorrect read-modify-write sequence in lpuart_flush_buffer() that
was reading from UARTPFIFO and writing to UARTCFIFO instead of
operating solely on the latter.

Fixes: 9bc19af9 ("tty: serial: fsl_lpuart: Flush HW FIFOs in .flush_buffer")
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Reported-by: NVivien Didelot <vivien.didelot@gmail.com>
Tested-by: NVivien Didelot <vivien.didelot@gmail.com>
Tested-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NFabio Estevam <festevam@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Jiri Slaby <jslaby@suse.com>
Link: https://lore.kernel.org/r/20191004215537.5308-1-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There are two parts which should be fixed. The first one is to assigned
uartps_major at the end of probe() to avoid complicated logic when
something fails.
The second part is initialized uartps_major number to 0 when last device is
removed. This will ensure that on next probe driver will ask for new
dynamic major number.

Fixes: ab262666 ("serial: uartps: Use the same dynamic major number for all ports")
Reported-by: NPaul Thomas <pthomas8589@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/d2652cda992833315c4f96f06953eb547f928918.1570194248.git.michal.simek@xilinx.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Call uart_unregister_driver() conditionally instead of
unconditionally, only if it has been previously registered.

This uses driver.state, just as the sh-sci.c driver does.

Fixes this null pointer dereference in tty_unregister_driver(),
since the 'driver' argument is null:

  general protection fault: 0000 [#1] PREEMPT SMP KASAN PTI
  RIP: 0010:tty_unregister_driver+0x25/0x1d0

Fixes: 238b8721 ("[PATCH] serial uartlite driver")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: stable <stable@vger.kernel.org>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Link: https://lore.kernel.org/r/9c8e6581-6fcc-a595-0897-4d90f5d710df@infradead.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Following an incorrect indentation reported to me by Dan Carpenter, I
noticed that the SysRq lines were inherited from the lpuart driver[1] (note
how the 'continue' is aligned to 'sport->port.sysrq = 0') and we have never
actually tested the SysRq support.

'sport->sysrq = 0' is not necessary neither before nor after 'continue',
because sysrq will already be 0 after uart_handle_sysrq_char() will finish.
Also, since the LINFlexD driver never called uart_handle_break(), sysrq
would have never been set to a nonzero value, so uart_handle_sysrq_char()
was not going to do anything.

Break conditions are detected based on a null data byte along with a
framing error (stop bit sampled to 0).

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/tty/serial/fsl_lpuart.c?h=b3e3bf2ef2c74f5ce5c19510edbbb9bfc1d249c2#n659

Fixes: 09864c1c ("tty: serial: Add linflexuart driver for S32V234")
Signed-off-by: NStefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Reported-by: Nkbuild test robot <lkp@intel.com>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20190918184439.7465-1-stefan-gabriel.mirea@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As platform_get_irq() now prints an error when the interrupt does not
exist, scary warnings may be printed for optional interrupts:

    sh-sci e6550000.serial: IRQ index 1 not found
    sh-sci e6550000.serial: IRQ index 2 not found
    sh-sci e6550000.serial: IRQ index 3 not found
    sh-sci e6550000.serial: IRQ index 4 not found
    sh-sci e6550000.serial: IRQ index 5 not found

Fix this by calling platform_get_irq_optional() instead for all but the
first interrupts, which are optional.

Fixes: 7723f4c5 ("driver core: platform: Add an error message to platform_get_irq*()")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Reviewed-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20191001180743.1041-1-geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The sifive serial driver implements earlycon support, but unless
another driver is built in that supports earlycon support it won't
be usable.  Explicitly select SERIAL_EARLYCON instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NPaul Walmsley <paul.walmsley@sifive.com>
Link: https://lore.kernel.org/r/20190910055923.28384-1-hch@lst.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

'exit' functions should be marked as __exit, not __init.

Fixes: c10b1332 ("tty: serial: Add RDA8810PL UART driver")
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20190910041702.7357-1-christophe.jaillet@wanadoo.frSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

'exit' functions should be marked as __exit, not __init.

Fixes: fc60a8b6 ("tty: serial: owl: Implement console driver")
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20190910041129.6978-1-christophe.jaillet@wanadoo.frSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add PIO mode support in receive and transmit path with RX interrupt
trigger of 16 bytes for Tegra194 and older chips.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-13-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Standard UART controllers support +/-4% baud rate error tolerance.
Tegra186 only supports 0% to +4% error tolerance whereas other Tegra
chips support standard +/-4% rate. Add chip data for knowing error
tolerance level for each soc. Creating new compatible for Tegra194
chip as it supports baud rate error tolerance of -2 to +2%, different
from older chips.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-12-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support to adjust baud rates to fall under supported tolerance
range through DT.

Tegra186 chip has a hardware issue resulting in frame errors when
tolerance level for baud rate is negative. Provided entries to adjust
baud rate to be within acceptable range and work with devices that
can send negative baud rate. Also report error when baud rate set is
out of tolerance range of controller updated in device tree.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-11-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support to use 8 bytes trigger for Tegra186 SOC.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-9-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Set maximum number of UART ports to 8 as older chips have 5 ports and
Tergra186 and later chips will have 8 ports. Add this info to chip
data. Read device tree compatible of this driver and register uart
driver with max ports of matching chip data.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-8-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Chips prior to Tegra186 needed delay of 3 UART clock cycles to avoid
data loss. This issue is fixed in Tegra186 and a new flag is added to
check if FIFO mode is enabled. chip data updated to check if this flag
is available for a chip. Tegra186 has new compatible to enable this
flag.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-7-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Report overrun/parity/frame/break errors to top tty layer. Add support
to ignore break character if IGNBRK is set.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-5-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

FIFO reset/flush code implemented now does not follow programming
guidelines. RTS line has to be turned off while flushing FIFOs to
avoid new transfers. Also check LSR bits UART_LSR_TEMT and UART_LSR_DR
to confirm FIFOs are flushed.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-4-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This avoids two race conditions from the UART shutdown sequence both
leading to 'Machine check error in AXI2APB' and kernel oops.

One was that the clock was disabled before the DMA was terminated making
it possible for the DMA callbacks to be called after the clock was
disabled. These callbacks could write to the UART registers causing
timeout.

The second was that the clock was disabled before the UART was
completely flagged as closed. This is done after the shutdown is called
and a new write could be started after the clock was disabled.
tegra_uart_start_pio_tx could be called causing timeout.

Given that the baud rate is reset at the end of shutdown sequence, this
fix is to examine the baud rate to avoid register access from both race
conditions.

Besides, terminate the DMA before disabling the clock.
Signed-off-by: NAhung Cheng <ahcheng@nvidia.com>
Signed-off-by: NShardar Mohammed <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-3-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support to ignore read characters if CREAD flag is not set.
Signed-off-by: NShardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: NKrishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-2-git-send-email-kyarlagadda@nvidia.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The sequence of arguments which was passed to handle_lsr_errors() didn't
match the parameters defined in that function, &lsr was passed to flag
and &flag was passed to lsr, this patch fixed that.

Fixes: b7396a38 ("tty/serial: Add Spreadtrum sc9836-uart driver support")
Signed-off-by: NChunyan Zhang <chunyan.zhang@unisoc.com>
Signed-off-by: NChunyan Zhang <zhang.lyra@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190905074151.5268-1-zhang.lyra@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As documented in the data-sheet, the transmitter must be disabled before
activating AutoCTS or auto transmitter flow control. Accordingly, the
transmitter must be enabled after AutoCTS or auto transmitter flow
control gets deactivated.
Signed-off-by: NChristoph Vogtländer <c.vogtlaender@sigma-surface-science.com>
Link: https://lore.kernel.org/r/20190904121746.4641-1-c.vogtlaender@sigma-surface-science.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 391f93f2 ("serial: core: Rework hw-assisted flow control
support") has changed the way the AutoCTS mode is handled.

According to that change, serial drivers which enable H/W AutoCTS mode must
set UPSTAT_AUTORTS, UPSTAT_AUTOCTS and UPSTAT_AUTOXOFF to prevent the
serial core from inadvertently disabling RX or TX. This patch adds proper
handling of UPSTAT_AUTORTS, UPSTAT_AUTOCTS and UPSTAT_AUTOXOFF flags.
Signed-off-by: NChristoph Vogtländer <c.vogtlaender@sigma-surface-science.com>
Link: https://lore.kernel.org/r/20190904121141.4570-1-c.vogtlaender@sigma-surface-science.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/fsl_linflexuart.c:907:3-8: No need to set .owner here. The core will do it.

 Remove .owner field if calls are used which set it automatically

Generated by: scripts/coccinelle/api/platform_no_drv_owner.cocci

Fixes: b953815b819b ("tty: serial: Add linflexuart driver for S32V234")
CC: Stefan-gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Signed-off-by: Nkbuild test robot <lkp@intel.com>
Reviewed-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20190825142837.zt3hpa22c7iofg3v@48261080c7f1Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The "fsl,s32-linflexuart" compatible string is too generic. Make it SoC
specific.
Signed-off-by: NStefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Link: https://lore.kernel.org/r/20190823191115.18490-4-stefan-gabriel.mirea@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The sprd serial console can work with only 26M fixed clock,
but the probe() is returning fail if the clock "enable" is not
configured in device tree.

This patch will fix the problem to let the uart device which is
used for console can be initialized even missing "enable" clock
configured in devicetree. We should make sure the debug function
as available as we can.
Signed-off-by: NChunyan Zhang <chunyan.zhang@unisoc.com>
Signed-off-by: NChunyan Zhang <zhang.lyra@gmail.com>
Reviewed-by: NBaolin Wang <baolin.wang@linaro.org>
Tested-by: NBaolin Wang <baolin.wang@linaro.org>
Link: https://lore.kernel.org/r/20190826072929.7696-4-zhang.lyra@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use console_initcall to save the console index we selected on the
command line to sprd_console before probe finished. Thus we can
make different processes to the uart devices during initialization
according to whether it is used for console.
Signed-off-by: NChunyan Zhang <chunyan.zhang@unisoc.com>
Signed-off-by: NChunyan Zhang <zhang.lyra@gmail.com>
Reviewed-by: NBaolin Wang <baolin.wang@linaro.org>
Tested-by: NBaolin Wang <baolin.wang@linaro.org>
Link: https://lore.kernel.org/r/20190826072929.7696-3-zhang.lyra@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When calling sprd_console_setup(), sprd_uart_port probably is NULL,
we should check that first instead of checking its items directly.

Also we should check membase to avoid accessing uart device before
its initialization finished.
Signed-off-by: NChunyan Zhang <chunyan.zhang@unisoc.com>
Signed-off-by: NChunyan Zhang <zhang.lyra@gmail.com>
Reviewed-by: NBaolin Wang <baolin.wang@linaro.org>
Tested-by: NBaolin Wang <baolin.wang@linaro.org>
Link: https://lore.kernel.org/r/20190826072929.7696-2-zhang.lyra@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 18dfef9c ("serial: atmel: convert to irq handling
provided mctrl-gpio"), the GPIOs interrupts are handled by
mctrl_gpio_irq_handle().
So, atmel_get_lines_status() can be completely killed and replaced by :
atmel_uart_readl(port, ATMEL_US_CSR);
Suggested-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NRichard Genoud <richard.genoud@gmail.com>
Link: https://lore.kernel.org/r/20190826071752.30396-1-richard.genoud@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This should help to avoid unnecessary gaps in transmission while
adding little overhead due to low default Tx threshold level (2
bytes).
Signed-off-by: NSergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-6-git-send-email-sorganov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

imx_set_termios(): avoid writing baud rate divider registers when the
values to be written are the same as current. Any writing seems to
restart transmission/receiving logic in the hardware, that leads to
data breakage even when rate doesn't in fact change. E.g., user
switches RTS/CTS handshake and suddenly gets broken bytes.
Signed-off-by: NSergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-5-git-send-email-sorganov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

imx_set_termios(): disabling individual interrupt requests in UART for
duration of the routine is pointless. Get rid of it.
Signed-off-by: NSergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-4-git-send-email-sorganov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

imx_set_termios(): stopping receiver and transmitter does harm when
something that doesn't touch transmission format/rate changes, such as
RTS/CTS handshake.

OTOH, it does no good on baud rate or format change, as
synchronization on upper-level protocols is still required to do it
right.

Therefore, just stop doing it.
Signed-off-by: NSergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-3-git-send-email-sorganov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

imx_set_termios(): remove busy-waiting "drain Tx FIFO" loop. Worse
yet, it was potentially unbounded wait due to RTS/CTS (hardware)
handshake.

Let user space ensure draining is done before termios change, if
draining is needed in the first place.
Signed-off-by: NSergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-2-git-send-email-sorganov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

A recent change split the insertion loop into two parts. The first part
accessed bytes 0, 1, ... (rxlen - 2), and the second part by mistake
took offset `rxlen` instead of the correct `rxlen - 1`. So one byte was
not stored, and the final access wrote past the end of the rx_buf.

Fixes: 9c12d739 (tty: max310x: Split uart characters insertion loop)
Signed-off-by: NJan Kundrát <jan.kundrat@cesnet.cz>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/13ea227620aaad8a7231d42ed03a8508297d4eb3.1567027079.git.jan.kundrat@cesnet.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

spinlock can be initialized automatically with DEFINE_SPINLOCK()
rather than explicitly calling spin_lock_init().
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20190827114614.102037-1-weiyongjun1@huawei.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There may be setups, where legacy interrupts are not available. This is
the caese, e.g., when Linux runs as guest (aka. non-root cell) of the
partitioning hypervisor Jailhouse. There, only MSI(-X) interrupts are
available for guests.

But the 8250_pci driver currently only supports legacy ints. So let's
enable MSI(-X) interrupts.

Nevertheless, this needs to handled with care: while many 8250 devices
actually claim to support MSI(-X) interrupts it should not be enabled be
default. I had at least one device in my hands with broken MSI
implementation.

So better introduce a whitelist with devices that are known to support
MSI(-X) interrupts. I tested all devices mentioned in the patch.
Signed-off-by: NRalf Ramsauer <ralf.ramsauer@oth-regensburg.de>
Link: https://lore.kernel.org/r/20190812112152.693622-1-ralf.ramsauer@oth-regensburg.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fintek F81504A/508A/512A is PCIE to 4/8/12 UARTs device. It's support
IO/MMIO/PCIE conf to access all functions. The old F81504/508/512 is
only support IO.
Signed-off-by: NJi-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
Link: https://lore.kernel.org/r/1565933249-23076-1-git-send-email-hpeter+linux_kernel@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>